AGP issues with a Radeon Pro, new XP system,

This may be a none issue but I was hoping to get some suggestions. I just installed XP pro on my two year old home-built( asus a7n8x deluxe, amd 3000+, radeon 9800pro, 1gig pc3200) and have suffered a loss of game performance. I have seen about a 20% decrease in benchmarks. I moved from win2k with the same hardware. I have been wrestling with this all day and this is what I know.

Tried both ATI and Omega drivers(latest).
Have killed as many services as I dare, in win2k I had 8.
Checked ide channels to make sure they are in DMA mode.
Drives were defragged after install.
All updates are done.

The one thing I have found is that Smartgart in the ATI utilities will not let me use my AGP multiplier. If I try to change it tells me the system is unstable and sets it back to 0. I have checked the bios and AGP is enabled along with AGP fast-write. Here's the rub, I haven't noticed a difference in gaming ( Doom3 and Half-life2). Can ATI be reporting my AGP setting incorrectly? Thank you for your help.

Did you install your MB chipset drivers ? try installing the AGP miniport driver again.

Thank you fastgame. Everything installed so well with XP it never occurred to me to install the nforce drivers. I haven't benchmarked yet but I do have full functionality in the ATI CP. Thank you again for showing me the way. Brad. Yes I feel dumb.

Nice catch, FG.

This is becasue Windows needs the MB drivers to recognise and fully use your MB. Without the driver, smartgart dosen't know what's your AGP bus speed and so sets it to 0 for anti-crashing reasons. Thus cutting performance.